The reputed boss of the Gambino crime family yesterday plea-bargained to an assault charge in a 1989 murder plot against a suspected informant.

John “Jackie the Nose” D’Amico, 74, faces up to three years for conspiring to commit an assault against Frederick Weiss.

According to papers filed in Manhattan federal court, D’Amico allowed co-defendant Joseph Watts, a reputed high-ranking Gambino associate, to recruit members of his crew for a hit on Weiss, a sanitation exec who had run afoul of then-mob boss John Gotti.

Authorities believe Weiss was instead murdered by New Jersey’s DeCavalcante mob — as a favor to “the Dapper Don.” Bruce Golding